The invention relates to an absorbent product, such as a sanitary towel, a panty liner or an incontinence pad, having a longitudinal direction and a transverse direction, comprising a liquid-permeable surface layer, a liquid-blocking surface layer and an absorption body arranged between the two surface layers, two side edges extending substantially in the longitudinal direction, a front edge, a rear edge, a front section and a rear section, the width of the rear section not exceeding 40 mm, and a fastening member to be fastened to the body of a user.
It is previously known to fasten absorbent products to the body by means of glue. See, for example, document WO 95/16424, WO 96/29968 and WO 98/28023.
The first two publications show products which are fastened around their periphery, i.e. within the region which is not to absorb fluid. The last-named publication (which is an example from a series of applications comprising 15 applications in total) describes a glue composition and specifies that the glue is preferably applied around the periphery of an absorbent product.
It has become increasingly common for women to wear a thong, as it is known, i.e. briefs having an extremely small rear section. The use of previously known body-fixed absorbent products together with a thong creates problems. The problem is that these products are designed for use together with conventional briefs and the product will therefore stick out beyond the edges of the thong, which may produce unsightly edge lines or creases on the clothes. Some of the discretion which is the very purpose of wearing a thong is thereby forfeited.
It has therefore been proposed to provide absorbent products intended for wear in connection with a thong. Absorbent products of this kind are designed with a very narrow rear section, which has the effect that the available liquid-receiving surface is smaller than for conventional absorbent products. Matching the known body-fixed absorbent products to the shape of a thong would result in a product having a substantially limited liquid-receiving surface, since the already limited available liquid-receiving surface would be further diminished as a result of glue being applied around the periphery of the product. This would result in a product having inadequate absorption properties and a heavily increased leakage risk as a consequence of fluid running onto the surface of the product and out over the edges thereof. In addition, there is a risk of the glued surfaces of such a product attaching to the sensitive mucous membranes of the user. Another problem with such a product, which is in close contact with the body, is that the passage of air and water vapour is hampered, which means that the product might eventually feel damp and hence uncomfortable to wear. In addition, there is a high risk of the glue sticking in the hairs of the user, which, apart from causing discomfort upon removal after use, also increases the risk of fluid leaking out over the edges of the product during use, since the product is not in close contact with the body.
There is thus a requirement to be able to provide a body-fixed absorbent product intended for wear together with a thong.
With the present invention, an absorbent product of the type discussed in the introduction has been realized, which product essentially avoids the above-stated problems. An absorbent product according to the invention is primarily characterized in that it is essentially triangular in shape and in that a fastening member is applied to the liquid-permeable surface layer only in the rear section of the product.
The fastening member has a fastening surface intended to be applied to the perineum of the user. As a result of the product being fastened to the perineum, the available liquid-receiving surface of the product will not significantly be affected.
A product according to the invention advantageously has a certain dimensional stability and rigidity. The rigidity of the product is important to prevent the product getting twisted, bent, cracked or torn during use. A product according to the present invention advantageously has flexural rigidity, at least in the longitudinal direction. In order to achieve the requisite rigidity in the product, together with maintained comfort, it is possible to use a plurality of materials of different rigidity. The product can thus have less rigid regions right out on the periphery of the product, the necessary flexural rigidity being obtained by virtue of a more rigid intermediate middle section.
Examples of more rigid materials suitable for use in the central part of the middle section are relatively thick layers of polypropylene film, polyethylene film and bonded fibre networks. By a relatively thick material layer is meant in this context a material layer having a layer thickness greater than ca. 0.2. mm. It is further possible to increase the rigidity of a plastics layer by mixing the plastic with talcum, chalk or some other rigidity-enhancing filler. The rigidity of the central part of the middle section can further be produced by means of rigid metal or wooden inlays, such as plates, rods, skeleton-like structures, or the like. The less rigid outer parts advantageously consist of one or more layers of soft, pliable material, such as plastics films and non-woven layers of the type commonly used as casing materials on absorbent products. The outer parts can further comprise absorbent materials, such as absorbent non-woven layers, cellulose fluff layers, tissue layers, or the like.
In order to achieve sufficient rigidity in the finished structure, it has been shown that the intrinsic rigidity of at least one component in the product should at least be greater than 100 N, measured according to ASTM D 4032-82 xe2x80x9cCircular Bend Procedurexe2x80x9d, which method is extensively described in EP 0 336 578. By rigidity is here meant the rigidity of a planar material layer.
The fact that the product has a certain dimensional stability and rigidity enables the product to be fixed tight against the body with just one fastening member. The product is easy to apply to the body, moreover, since only one fastening point fixes the product to the body. By fastening the product to the body within a region which is free from hair, the benefit is attained of fixing the product tight against the body. This increases the capacity of the product to adapt to the body of the user, thereby reducing the risk of leakage.
As a result of the adaptability of the product to the shape of the body, the product remains securely in place, even with the extremely small fastening surface arranged on the rear section of the product. During use, the product is in close contact with the body, thereby producing a controlled and well-defined target area for the secreted body fluid. This means that the absorption body of the absorbent product can be shaped such that the absorbent material is utilized to optimum effect.
According to one embodiment of the invention, the fastening surface is constituted by low-absorbency, self-bonding adhesive. Here, a low-absorbency adhesive means an adhesive which has sufficient adhesion to skin to ensure secure fastening of the product, whilst at the same time the adhesion is not so strong that it causes harm or injury when the product is removed. The self-bonding adhesive can be constituted, for example, by polyacrylates. In order to provide extra softness, the self-bonding adhesive can be slightly foamed, producing a slight padding of the fastening surface.
The fastening surface can also be constituted by friction agents, which can be made from a material of the tack-free hot metal type, for example. A suitable hot metal material for use in this connection is a material based on thermoplastic rubber, for example styrene-isoprene rubber (SIS), styrene-butadiene rubber (SBR), or styrene-ethylenebutadiene-styrene rubber (SEBS). Other hot metal materials can also be used, for example within the following groups: ethylene vinyl acetate copolymers, cellulose acetate butyrate, ethyl cellulose and acrylic materials.
Other examples of friction agents are foam-type materials and water-based materials, for example polyvinyl acetate.
According to another embodiment, the fastening surface can be constituted by hydrogel. The hydrogel is made from a material which does not irritate the mucous membranes of the user and can comprise polymers based on vinyl alcohol, polyacrylate, polymethacrylate, polyethylene oxide, polysaccharide, acrylamide, vinyl pyrrolidone, polyethers, amino acids or urethane, and mixtures, copolymers and derivatives thereof.
It is also possible to pre-treat the hydrogel, before it is applied to the product, in such a way that it has been fully dehydrated or at least to such an extent that the hydrogel is able to reabsorb liquid when exposed to wetting during use in an absorbent product. The hydrogel will hereupon absorb body fluid and swell to its original, predetermined shape, whilst at the same time acquiring a sticky surface which produces an adhesion of the product to the perineum of the user in a kind and gentle and comfortable manner. In the course of the absorption, a suction force is also created in the hydrogel, which helps the product to be held tight against the body of the user.
It is also, of course, possible for the fastening surface to be constituted by glue similar to that which is found within wound protection, for example sticking plaster.
It is also important for the fastening surface to be constituted by material which is neither irritating to the skin, nor causes discomfort when the product is removed.
The fastening surface arranged on the product according to the present invention can have a variety of shapes, such as, for example, rectangular, circular or triangular. It is also, of course, possible for the fastening surface to be constituted by a regular or irregular pattern of dots or dashes, for example.
It has been shown in measurements that the length of the perineum does not vary significantly amongst different women. The length of the perineum has thus been shown to range between 1 and 4 cm. The length of the perineum means the distance between the vaginal opening and anal orifice of the woman.
According to one embodiment of the invention, the fastening surface has a width of max. 15 mm in the transverse direction of the product and a length of max. 20 mm in the longitudinal direction of the product. If the fastening surface is circular in shape, its radius should not exceed 7.5 mm.
According to one embodiment of the invention, the fastening member is arranged in such a way that the distance from the rear edge of the product to the periphery of the fastening surface is max. 10 mm. The product will in this case have a tongue, which will be constituted by the region between the rear edge of the product and the periphery of the fastening surface. Such a tongue facilitates fastening of the product and also the removal of the product after use.
According to a further embodiment of the invention, the rear section of the product, in the region of the fastening member, has a width of max. 20 mm.
It is advantageous if the absorbent product follows the edge of the briefs, so that the possible liquid-receiving surface is as large as possible. A product offering the maximum possible width is also important from the leakage aspect. The risk of both lateral leakage past the briefs and staining of the latter is reduced, since the product is adapted to the shape of the briefs. The absorbent product according to the invention therefore has side edges which are curved in the direction in towards a centre line extending in the longitudinal direction of the product. Curved side edges also result in the product having an anatomically adapted shape. A product which follows the shape of the thong will also be very well concealed during use.
It has been shown that the front part of the majority of thongs on the market is sufficiently wide to allow the front section of the product to be designed with more freedom according to the absorbency requirements which might pertain. In order to fit in a thong, it has proved expedient for a product according to the invention to have a width ratio in the transverse direction of the product, between the front section of the product and the rear section of the product, which is within the range of 2:1-4:1.
To prevent the product, during use, extending so far back that it is clearly visible when worn together with a thong, it is expedient for the rear section of the product to have a length ranging from 80 mm to 140 mm and for the total length of the product to be no greater than ca. 260 mm.